A spatial light modulator has a modulation plane in which a plurality of pixels for modulating amplitude or phase of input light and outputting light after modulation are arrayed, and can perform the amplitude modulation or the phase modulation in each pixel for the input light and output the light after modulation. Configurations and uses according to various aspects are known for the spatial light modulator. For example, technology described in Non Patent Document 1 intends to correct aberration of an optical system at the time of fundus measurement, using a spatial light phase modulator (PPM: Programmable Phase Modulator) to be a type of spatial light modulator and capable of performing only phase modulation.